Multi-treatment sterilization devices of the above type are well known in the art. Generally such devices are used to sterilize closures and caps, such as rubber stoppers for pharmaceutical containers and the like. The plurality of closures are subjected to several different treatments such as washing, sterilizing and drying in a multi-purpose container, wherein the closures being all in a heap in the container. Rubber stoppers are usually also siliconized, all within the same multi-purpose container. DE4409659 discloses an example of a cleaning and sterilizing installation.
After washing and siliconization but before steam sterilization, the closures are usually subjected to a pre-vacuum step in order to evacuate the presence of air and other unwanted fluids in the multi-purpose container. The un-evacuated air might have an isolating effect which may make the sterilization step more difficult and time consuming. During the sterilization treatment the multi-purpose container is supplied with heated steam until the closures have obtained sterilization temperature during an appropriate time.
The sterilized closures are usually subjected to an additional vacuum step before drying. The closures are dried with the supply of hot sterile air, for instance supplied in time intervals to the container. Subsequently the closures are subjected to a cooling treatment by cooled sterile air.
However, the sterilization may be troublesome for delicate closures, especially for some material compositions. The sterilization can create clumping of closures and in worst case the closures may be damaged due to the conditions in the multi-purpose container.
It is also desirable to reduce the process time in the multi-purpose container.
Finally it is advantageous to provide a robust, cost effective and reliable high quality multi-treatment sterilization device.